One of the foundations of surgery is the use of sutures to re-appose soft tissue, i.e., to hold tissue in a desired configuration until it can heal. In principle, suturing constitutes introducing a high tensile foreign construct (looped suture) into separate pieces of tissue in order to hold those pieces in close proximity until scar formation can occur, establishing continuity and strength between tissues. Sutures initially provide the full strength of the repair, but then become secondarily reinforcing or redundant as the tissue heals. The time until tissue healing reaches its maximal strength and is dependent on suture for approximation, therefore, is a period of marked susceptibility to failure of the repair due to forces naturally acting to pull the tissues apart.
Conventional sutures provide a circular or single-point cross-sectional profile extended over the length of the suture material. Such a suture has the great benefit of radial symmetry, which eliminates directional orientation, allowing the user (e.g., physician, surgeon, medic, etc.) to not have to worry about orienting the suture during use. However, a considerable disadvantage of conventional sutures with a single-point cross-section is that this construct cannot effectively distribute force, and instead, actively concentrates force at a geometric point (e.g., the point at the leading edge of the circle) creating a sharp edge in the axial dimension. Under these conditions, the tissue is continuously exposed to tension, increasing the likelihood that stress concentration at a geometric point or sharp edge will cut through the tissue.
More recently, as described in U.S. Pat. No. 9,237,889 (the entire contents of which are expressly incorporated herein by reference), Dr. Gregory Dumanian has invented a macroporous mesh suture that advantageously leverages the body's natural healing response to resist twice the magnitude of load as that of conventional sutures before pulling through. This macroporosity encourages tissue growth in, around, and through the entire suture.
For most applications, the size (e.g., diameter) of conventional sutures are less than 1 mm. It is common for needles to be directly attached to standard sutures, with a drilled hole creating an interval void at the end opposite the sharp tip. This drilled hole receives the first end of the suture to be directly attached. Alternatively, the suture is placed (i.e. swaged) onto a flat or v-shaped channel located at the end of the needle opposite the sharp tip, with the channel then being bent or crimped to achieve a direct attachment of the needle to the first end of the conventional suture.
Macroporous mesh sutures are much larger than conventional sutures. This creates a problem of needle attachment because the size of such macroporous mesh sutures range from 1 mm to 5 mm or more. Standard direct attachments via drill holes or channels at the end of the needle away from its sharp tip would require an introducing element or trocar far larger than a standard needle. Examples of a large introducing elements or trocars connected to macroporous meshes is in the art of gynecology slings and tapes. Far better, however, is for the introducing agent (needle) to be smaller than the macroporous mesh suture to minimize tissue trauma. Macroporous mesh sutures do not require a large hole, as the suture collapses during passage through tissue. A mesh suture directly attached to a needle that large would not only be difficult and cumbersome for the surgeon to use, the larger needle diameters required would unnecessarily create large holes in the tissue during use and therefore unnecessarily harm normal tissue during use. For this reason, a method of indirectly attaching a mesh suture to a standard sized needle is described herein. For example, to attach a mesh suture directly into a hole or channel in a conventional surgical needle, the hole, channel, and needle itself would need to be the same approximate size as the mesh suture. A mesh suture directly attached to a needle that large would not only be difficult and cumbersome for the surgeon to use, the larger needle diameters required would unnecessarily harm normal tissue during use. For this reason, a method of indirectly attaching a mesh suture to a standard sized needle is described herein.